The NBN twilight zone

The Coalition's multi-technology mix NBN poses technical and rollout coordination challenges that could well leave quite a few premises out in the cold.

Speaking at CommsDay NBNRebooted held on November 17 Communications minister Malcolm Turnbull addressed the issue of National Broadband Network (NBN)-related complaints to the Telecommunications Industry Ombudsman (TIO) when he stated “this is why the NBN Co is forecasting it will increase the number of serviceable premises in brownfield areas from 67 per cent of the total premises passed to 81 per cent of premises passed.”

This startling admission that 19 to 33 per cent of premises will not be connected to the NBN as the rollout passes through an area is clearly unacceptable and Australians should wonder why Turnbull has not directed NBN Co to reduce the figure to 0 in recently commenced rollout areas and to remediate 100 per cent of premises that have been classified “service class 0” within one or two weeks of a the rollout being completed in an area.

Should NBN Co provide greater transparency by providing a list of rollout areas that have been completed and are currently underway and an indication of the number of premises without NBN connections in each area?

Technical and rollout coordination challenges

The multi-technology mix (MTM) NBN poses technical and rollout coordination challenges that NBN Co may defer rather than tackle as streets and suburbs are connected to the NBN over the next couple of years.

It is now more than a year since NBN Co commenced the process to transition to the MTM NBN from the ambitious effort to overbuild the old and degrading copper access network (CAN) with Fibre-to-the-Premises (FTTP).

Up to 30 per cent of premises in some areas will be detrimentally affected by the adoption of the MTM NBN and what this means is that affected premises won’t be connected to the NBN or will suffer degraded connections for 18 or more months after the rollout has been completed in the local area.

Don’t worry though, according to the government’s MyBroadband website if the area has HFC, FTTN or FTTP premises that aren’t connected to the NBN will still receive an ‘A’ rating even though two or more years may pass before something is done about identifying and connecting premises classified as “service class 0”, further highlighting the nonsense being fed to consumers by the government about the quality and availability of their access to broadband.

The problem faced by NBN Co today is not new but it has been exacerbated by the government’s decision to increase the number of technologies to be used for the NBN, a construction approach that permits construction partners to miss premises and to connect premises using degraded or over-utilised infrastructure.

Speaking at the Telstra AGM about the NBN Co agreement renegotiation CEO David Thodey said “we do say that it is very dependent on the government processes, but it is getting through all the considerations involved in moving to fibre to the node and how customers are treated in that process.”

Australians might have expected that a CAN overbuild with FTTP would mean that all of the premises in an area where the rollout has been completed would be FTTP active and ready for customer connections to the NBN.

But this expectation has not eventuated and the result has been a steady but relatively small number of complaints to the TIO. During the 2013-2014 financial year, NBN Co connected 140,000 new customers and 3982 complaints were made to the TIO. Significantly NBN related complaints were 25 per cent of complaints about not being able to get an internet connection and 40 per cent of complaints about installation contractors missing appointments.

Multi-technology mix challenges

The MTM NBN will utilise the existing Hybrid-Fibre Coax (HFC) network, Fibre-to-the-Node (FTTN) and Fibre-to-the-Basement (FTTB) for about 70 per cent of premises. What this means is the specialist technology based rollout teams will operate in technology designated areas, for example an area that is to receive FTTN, and unless there is close coordination between the different rollout teams there will be unwanted side effects such as multi dwelling units (MDUs) being bypassed until months or years later when a FTTB team arrives to connect the building to the NBN.

Another example is the use of VDSL2 with vectoring for the FTTN technology. All of the copper pairs in a bundle or cable must be VDSL2 with vectoring for the technology to operate correctly, so if there is even one copper pair in a bundle or cable used for an alternate technology such as ISDN, ADSL2 or utility signalling then the performance for every connection will degrade significantly and interference can occur at pits and other locations where cables are split.

While this might appear to be a problem we should appreciate that the government quickly identified a solution which was to set the NBN performance bar so low that most Australian’s would achieve the government’s target connection speeds without shifting from their existing ADSL service.

In December 2013, Turnbull wrote that the MTM “model would have a peak funding requirement of $41 billion ($32 billion less than business as usual [the FTTP model]), deliver 25 mbps to 43 per cent by 2016, 50 mbps to 91 per cent by 2019 and be completed in 2020”.

Turnbull appears to have been overly optimistic because NBN Co has been careful to insert “up to” before performance targets in current documentation and it is noticeable that the timeframes have been extended in the latest NBN Co 2014-2017 Corporate Plan with added disclaimers about the accuracy of the predictions beyond 2015.

In most suburbs there are houses, units, apartments, shops, office parks, etc. and this means that the likelihood of premises being affected by legacy ISDN, ADSL or other technologies could affect 10 to 15 per cent of premises. And if FTTB is not rolled out to multi-dwelling units as FTTN is rolled out in an area then we should expect another 10 to 15 per cent of premises to be affected by the mismatched technologies in the copper cables.

Similarly for FTTB to be effective all of the premises in a multi-dwelling unit must move to VDSL2 or VDSL2 with vectoring at the same time. If for some reason this does not occur then the likelihood of interference between the copper pairs as they wind their way to the apartments is high and this will mean that all of the premises in the building will suffer a degraded service.

If there is degraded copper in a bundle or cable this will have a detrimental effect on VDSL2 with vectoring and the result will be a service that may be so bad that the cable or bundle needs to be replaced.

Turnbull has often spoken about the rollout teams replacing degraded copper with fibre but there is no evidence available that this is happening or that the government intends to meet this promise.

Complaints have started to surface from people frustrated with being told by construction teams or service providers that their connection to the street or down the street to the nearest pillar is degraded and something would be done in the future without any indication of when this might be.

Winners and losers

So what we can now assume with some degree of confidence is that about 70 per cent of Australian premises will be connected to the NBN using HFC, FTTN, FTTB or with existing technologies for one or more years after the rollout has “finished” in a street or suburb. If you’re in a FTTN designated area for example with degraded copper you should not expect fibre to be used to replace the copper because the nodes being rolled do not appear to be fitted with FTTP capability and even though Turnbull has made a lot of noise about offering Fibre on Demand (FOD) at some time in the future this holds little promise if the UK BT’s costly FOD failure for BT is any guide.

Adding the HFC network to the NBN will create a number of challenges for NBN Co. The immediate benefit will be the large number of existing HFC users that NBN Co can claim to have “added” to the NBN which will provide the government with something to crow about in the lead-up to the next Federal election.

Uncertainty remains about the HFC build rules and whether HFC going live in an area will trigger the 18 month countdown before the CAN in the area is turned off. Or will the government leave the CAN operating for two or more years until remediation and FTTB rollouts to multi dwelling units occur?

And the HFC network will need to be upgraded more than once over the next five to eight years to provide up to 100 / 8 Mbps (to match iiNets offering) or up to 100 / 40 Mbps and then up to 1000 / 400 Mbps if DOCSIS 3.1 is implemented. Infrastructure upgrades will be required as the Australian HFC networks are old and this will have an impact on connection performance.

But the most significant aspect of any upgrade to the HFC network will be the need to redistribute nodes to ensure that there is capacity available for customers at peak times. A significant weakness of the existing HFC and CAN ADSL2 networks is the lack of capacity and congestion at most times of the day, but especially during peak hours when access slows to a crawl.

NBN Co is likely to target a range of existing problems with the HFC networks but we should not expect the work to be carried out quickly and in some areas the remediation work will still be going on as this decade ends. It is not that NBN Co does not want to do the remediation work, but the rollout is hindered in part due to the failure to significantly increase rollout and remediation team numbers.

The only way to increase the pace of the rollout while the personnel shortage is addressed will be to focus available contractors on the easy to connect premises first.

In the areas covered by the HFC network there will be a need to transition several million ISDN and ADSL users onto the NBN HFC network and this will be a significant undertaking that could result in an exponential escalation in complaints to the TIO. 

For some, the transition to the NBN will be delayed until after the 2016 election as NBN Co works to finalise integration of the HFC network, focuses on existing HFC users and carries out remediation of the network necessary to achieve 100 / 8 Mbps.

NBN Co chairman Dr Ziggy Switkowski stated recently that NBN Co will provide design rules for the HFC, FTTN and FTTB networks in the new year and this should provide some of the answers to questions about how the MTM NBN will be implemented but we won’t have the full picture until NBN Co publicly states what it will do to overcome the technical and rollout coordination challenges and when this will occur.

Mark Gregory is a Senior Lecturer in the School of Electrical and Computer Engineering at RMIT University.